

class TextureUnit(object):
    colour_op = {
        'MIX'         : 'modulate' , # Ogre Default - was "replace" but that kills lighting
        'ADD'         : 'add'      ,
        'MULTIPLY'    : 'modulate' ,
        #'alpha_blend' : ''         ,
    }
    colour_op_ex = {
        'MIX'        : 'blend_manual'         ,
        'SCREEN'     : 'modulate_x2'          ,
        'LIGHTEN'    : 'modulate_x4'          ,
        'SUBTRACT'   : 'subtract'             ,
        'OVERLAY'    : 'add_signed'           ,
        'DIFFERENCE' : 'dotproduct'           , # best match?
        'VALUE'      : 'blend_diffuse_colour' ,
        }

    tex_address_mode = {
        'REPEAT'  : 'wrap'   ,
        'EXTEND'  : 'clamp'  ,
        'CLIP'    : 'border' ,
        'CHECKER' : 'mirror'
    }